Amiri et al

Turbulent Velocity Fluctuations as Affected by Biotic and
Abiotic Windbreaks under Field Conditions

Iraj Amiri1, Javad Taei2*, Mohammad
Reza Ekhtesasi3

and Ali Reza Shahryari4

1Department
of Natural Resources, Faculty of Agriculture, University Of
Jiroft, Jiroft, Iran

2Department
of plant sciences, Faculty of Agriculture, University Of
Jiroft, Jiroft, Iran

3Faculty
of Natural Resources, Yazd University, Yazd, Iran

4Faculty
of Natural Resources, University Of Zabol, Zabol, Iran

*Corresponding Author’s E-mail:
ga_agric @yahoo. com

Abstract:

Windbreaks have been used for centuries to shelter crops
from wind damage and to protect soils from wind erosion.
This study was performed in 5 steps to evaluate the effects
of biotic and abiotic windbreaks on mean horizontal flow and
turbulent velocity fluctuations under field conditions.
These steps included granolometery analyzing, determination
of field threshold velocity of soil erosion, estimation of
acceptable wind speed, optimizing windbreak distance and
wind speed recording. Two kinds of windbreaks were used in
this study, biotic windbreak (Tamarix aphylla) with
45% density and abiotic windbreak (Mud wall) with 100%
density. Results of field experiment showed that optimized
distances for abiotic and biotic windbreak are respectively
observed at 7.87h and 4.5h after windbreak. Finally mud wall
is applicable for high decreasing wind speed at the back of
windbreak but its high wind speed fluctuation and high
turbulence were limited to these windbreaks in agro
ecosystem. Tamarix aphylla with 45% density is
applicable for medium decreasing of wind speed and creating
low turbulence after windbreak.